Optical films having an uneven structure of nanometer scale (nanostructure) are known for their excellent antireflective properties. This uneven structure has a continuously varying refractive index from the air layer to the substrate, thereby capable of reducing the reflected light significantly.
Although such optical films have excellent antireflective properties, the uneven structure on the surface may cause easy spread of dirt such as fingerprints (sebaceous dirt) sticking thereon and may further cause difficulty in wiping off such dirt present between projections. Such sticking dirt has a reflectance that is very different from the reflectance of the optical film, and thus is noticeable. This strongly increases demand for optical films having excellent antifouling properties as well as water repellency and oil repellency. For example, Patent Literatures 1 to 3 propose structures in which a layer of a fluorine-based material is formed on the surface of the uneven structure or a fluorine-based material is added to the uneven structure.